This invention relates to tubular molds for the continuous casting of molten metals, provided with an outer cooling water jacket for the cooling of the tubular inner mantle of the mold inside of which the solidification of the continuous cast ingot begins.
A main problem arising in the molds of the above described kind, is that of obtaining a uniform distribution of the flow of the cooling water in the cooling jacket. In fact, since the overall heat transmission coefficient from the molten metal to the cooling water through the inner mantle of the mold depends essentially on the flow rate of the cooling water in the cooling jacket, it is hence necessary that the said flow rate be substantially equal all around the whole periphery of the inner mantle of the mold. In fact, in the absence of such an uniform distribution of the flow rate of the cooling water in the cooling jacket, the heat exchange intensity between molten metal and water will vary from location to location even in the same peripheral zone of the inner mantle of the mold, which has as a consequence differences in the thickness of the outer solidified metal layer of the ingot being formed, the so called "crust", which crust has to withstand the ferrostatic pressure exerted by the molten core of the ingot, until completion of the solidification of the ingot. The above differences in the thickness of the crust of the ingot are the chief cause of deformations in the cross section of the cast ingots. They may also be the cause of breakages of the crust of the ingot, with the consequent need of interrupting the casting process, due to the outflow of liquid metal from the core of the ingot being formed.
In the known tubular molds of this kind, the cooling water was fed to the cooling jacket of the mold by means of feed pipes opening into small manifolds disposed at the inlet end of the cooling jacket.
The above and other similar prior art solutions are rather complicated, whilst they do not assure the perfect uniformity of flow of the cooling water through the cooling jacket of the mold.
It is accordingly the main object of the present invention to provide a water cooled tubular mold for the continuous casting of metals, in which the flow rate of the cooling water through the cooling jacket of the mold is uniform.
According to a main aspect of the present invention, the above object is accomplished by providing, between the cooling water feed pipes and the cooling water inlet ports of the cooling jacket of the mold, an inlet manifold chamber which on its side near the outlet ports of the feed pipes has a cross sectional area greater than the sum of the cross sectional areas of the cooling water feed pipes outlets, the cross sectional area of the said inlet manifold chamber decreasing from the said side toward its opposite side in which the inlet ports of the cooling jacket of the mold are formed.
Preferably, the said inlet manifold chamber is formed by a funnel shaped mantle, surrounding the lower end of the cooling jacket of the mold, and extending from the lower end of the mold up to substantially one half of its height, where it is closed by an end plate provided with openings through which the outlet ends of the cooling water feed pipes are conducted. The above and other features and advantages of the present invention will be better evident from the following specification made with reference to the accompanying drawings.